The webpage you reference gives instructions for adding any of the Windows Explorer command buttons that Microsoft includes with Windows 7 to the Windows Explorer toolbar. That's not what you want. Those do not include New Text Document.

That exterprise is arduous. It requires not only extensive finagling with the Windows Registry, but also creating a custon icon and finding an executable to carry out the command. Just thinking about it has me wanting to lie down.

Can you be tempted with something doable? How about something one-click but not a button? This little AutoHotKey thingy remaps the middle mouse button when the context is Windows Explorer to simulate the keypresses

Alt+f
m
t

This works whenever those keypresses work. Some programs customize the menus. When files of certain types are selected (e.g., .vbs files, .js files), Windows modifies the file menu.

I found an obscure program called Paste As File http://paf.pen.io/ It adds an entry in the right click context menu so that when you click on it, it paste the contents of the clipboard to a new file in the current folder ready for renaming. This is exactly what I was looking for. I was only interested in working with text files but this little jewel of a program goes even further; it can paste to many different file formats besides TXT including RTF, PDF, JPG, PCX, PNG, TGA, GIF, & TIF. Also, if you want HTML you can change the extension of the TXT to HTML. The developer states it can be used working with PHP & CSS as well. It's regularly updated and only costs $10.55 and you get free upgrades. It's fantastic.